Bias-free terahertz generation from a silicon-compatible photoconductive emitter operating at telecommunication wavelengths
Abstract
We present a telecommunication-compatible bias-free photoconductive terahertz emitter composed of a bilayer InAs structure directly grown on a high-resistivity silicon substrate. The bilayer InAs structure includes p+-doped and undoped InAs layers, inducing a strong built-in electric field that enables terahertz generation without requiring any external bias voltage. A large-area plasmonic nanoantenna array is used to enhance and confine optical generation inside the photoconductive region with the highest built-in electric field, leading to the generation of a strong ultrafast photocurrent and broadband terahertz radiation. Thanks to a higher terahertz transmission through the silicon substrate and a shorter carrier lifetime in the InAs layers grown on silicon, higher signal-to-noise ratios are achieved at high terahertz frequencies compared with previously demonstrated bias-free terahertz emitters realized on GaAs. In addition to compatibility with silicon integrated optoelectronic platforms, the presented bias-free photoconductive emitter provides more than a 6 THz radiation bandwidth with more than 100 dB dynamic range when used in a terahertz time-domain spectroscopy system.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 27, 2022
- Source ID
- 10.1063/5.0098340
Entities
People
- Deniz Turan
- Mona Jarrahi
- Ping-keng Lu
- Xinghe Jiang
- Yifan Zhao
Organizations
- Office of Naval Research Global
- United States Department of Energy
- University of California